Ok 71 Block Stock Deck Height 11to 1 30 Over Pistons, 67 Heads 985 Casting, Milled 30,67 Rockers,heads 67cc?fel Pro Blue Ta 413 Cam, Ta Intake, 850 Holley, 10in 3500 Stall, Headers, 3.73 Gear. What Would The Compression Be, And Is This A Streetable Set Up On Pump Gas. This Is A New Motor Lost Old Motor To Hyper Piston Failure. This Is In A 71 Gs Conv. The Best It Ran Was 12.85 At 103 With 1.80 60ft On Drag Radials. I Drive This Car Every Day It Is Nice In Town And On Highway.
Sounds like a strong combo,pretty good parts matching.I would spend some $$ on some port/bowl work to the heads.Not sure what your true C.R would be but I think you might have to mix a bit of race gas IMHO.Later,Tony.
If we assume that your stock deck height, with the 11-1 pistons yeilds around .020 deck clearance, then your compression would be 11.75 to 1 If the pistons are .030 in the hole, then it will be 11.5 to 1. I am assuming that 11-1 piston is a flat top, with valve reliefs (7cc typically) You won't run either of those comp ratios on pump gas. You have to have dished pistons to run that small a chamber in the head, with that gasket, and keep the compression around 10-1, or just a touch higher. JW
Thanks For The Feed Back I Will Go With The Speed Pro Pistons,because I Would Like To Stay At That 10.1. The Heads Are Small Valve And Have Some Work Done To Them.
i have the same commpression and similar 113A cam, i can run pump 92 octane pump gas untill it gets above 80 degress then im ok unless i get on it. above 85, then i will pump up the octane, and i always run above 96 octane when i race. i also have polished combustion chambers, that semmed to help.
have it zero-decked with the speed pros and you will be about 10-10.25 with 0.042 gaskets. you might do some price shopping comparing the PAE Wisecos, TA conical dish and S-P's before you drop the cash. The first two are quite a bit lighter *I think*, and maybe not that much more $$.
I'm running the 113A cam also. I polished the heck out of my combustion chambers, have a true 10.13 to one compression. I run 93 octane all the time and have no pinging problems. And I have 34 degrees total advance all in by about 1500 or so.
If I Zero Deck The Block Will I Have Any Valve Clearance Problems? The Heads Are Already Cut 30 That I Know Of, And I Realy Like The 413 Cam.
Get notched pistons when you buy them. it's a good thing to do in case you choose to go with better heads and more lift in the future anyway. No gaurantees on clearance without notches. I have a hemi-killer cam which I think is close to the 413 and it barely clears with 030 off the heads and 035 off of the deck and no notches.
Running Poston's 113A cam, I have no clearance issues at all. My pistons are TRW aluminum 24 cc dished pistons. My block is decked to .003 and heads are 1967 430 heads with Stage 1 valves. The heads have been decked twice, but never shaved that I'm aware of.
